Cutting machine

Abstract

A cutting machine is provided with, at a distal end of a tool, a key protrusion that has a tapered section. The distal end of the tool can be inserted into an insertion hole of a bushing. The insertion hole is provided with a key groove into which the key protrusion is inserted. The tapered section of the key protrusion has first and second inclined surfaces. The first inclined surface is a surface twisted clockwise with respect to the axial center of the tool. The second inclined surface is a surface twisted counterclockwise with respect to the axial center of the tool. A tapered groove section of the key groove has first and second guide surfaces.

What is claim is: 
     
         1 - 5 . (canceled) 
     
     
         6 . A cutting machine, comprising:
 a main body frame;   a tool that has a shaft shape, is linearly movably disposed along the main body frame, and is driven to rotate; and   a rotation support unit including a rotating body provided with an insertion hole into which a distal end part of the tool along a direction of movement is inserted, wherein the rotating body is configured to rotate together with the tool that is inserted into the insertion hole,   wherein the tool is inserted into the insertion hole by moving in a first direction along an axial direction of the tool,   an engaging convex portion, which projects outwardly in a radial direction of the tool and extends along the axial direction of the tool, is provided on the distal end part of the tool,   the insertion hole extends along an axial direction of the rotating body, and includes an engagement groove recessed from an inner circumferential surface of the insertion hole and outwardly in a radial direction of the insertion hole, the engaging convex portion being inserted into the engagement groove,   the engaging convex portion includes:   a convex portion main body formed with a substantially constant width along the axial direction of the tool; and   a tapered portion disposed adjacent to the convex portion main body in the first direction, and including first and second inclined surfaces, a distance between which becomes smaller toward the first direction,   when the tool is viewed in the first direction, the first inclined surface is disposed in a counterclockwise direction with respect to a center in a widthwise direction of the tapered portion, and the second inclined surface is disposed in a clockwise direction with respect to the center in the widthwise direction of the tapered portion,   the first inclined surface is a surface that is twisted clockwise with respect to an axial center of the tool toward the first direction, and the second inclined surface is a surface that is twisted counterclockwise with respect to the axial center of the tool toward the first direction,   the rotating body includes an end surface facing toward a second direction that is a direction opposite to the first direction,   the engagement groove includes:   a tapered groove portion extending in the first direction from the end surface of the rotating body and including first and second guide surfaces, a distance between which becomes smaller toward the first direction, the tapered groove portion having a greater width than the tapered portion; and   a groove main body disposed adjacent to the tapered groove portion in the first direction, and formed with a substantially constant width along the axial direction of the rotating body,   when the insertion hole is viewed in the first direction, the first guide surface is disposed in the counterclockwise direction with respect to a center in a widthwise direction of the engagement groove, and the second guide surface is disposed in the clockwise direction with respect to the center in the widthwise direction of the engagement groove,   the first guide surface is a surface that is twisted clockwise with respect to an axial center of the insertion hole toward the first direction, and the second guide surface is a surface that is twisted counterclockwise with respect to the axial center of the insertion hole toward the first direction, and   the cutting machine further comprises a detection mechanism configured to detect a position of the rotating body in a direction of rotation, and the detection mechanism includes: a detectable portion that is disposed on an outer circumference of the rotating body, and that projects outwardly in a radial direction; and a detection sensor configured to detect the detectable portion.   
     
     
         7 . The cutting machine according to  claim 6 , wherein the engaging convex portion is disposed in an attachable and detachable manner on the distal end part of the tool. 
     
     
         8 . The cutting machine according to  claim 6 , wherein the tool includes a base end disposed in an opposite direction to the distal end part of the tool and connected to a drive mechanism configured to cause the tool to be driven to rotate, and the base end is rotatably supported by a second rotation support unit that is disposed on the main body frame.